In spite of active measles vaccination efforts in 2005 in southern Nigeria, re-emergence continues to occur. This study was carried out to ascertain the incidence of measles, severity, mortality and its complications, in order to enhance treatment and reduce under-five child mortality. Secondary data from the records in the measles ward of Oni Memorial Children’s Hospital, Ibadan was used. The period under investigation was 2005 to 2008, following the catch-up and follow-up measles vaccination exercise. Four hundred children between the ages of 5 months and 14 years were clinically diagnosed with measles from 2005 to 2008, of which 124 (31%) had complications. Among those with complications, 70 (56.5%) mortalities were observed, and as the children approached 14 years of age, incidence of measles reduced to 0%. Measles is still a major childhood problem in the southern part of Nigeria, even as the burden is more in northern Nigeria. This will invariably hamper global measles mortality reduction initiatives and the attainment of the fourth millennium development goal of reduction of under-five child mortality by 2015, hence the need for a coordinated and strategic mass vaccination effort to target unimmunized children.